A computer network is a collection of interconnected computing devices that can exchange data and share resources. In a packet-based network, the computing devices communicate data by dividing the data into small blocks called packets, which are individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. Dividing the data into packets enables the source device to resend only those individual packets that may be lost during transmission.
The Transmission Control Protocol (TCP) is a common transport-layer protocol by which network devices transport packets according to a packet-switching scheme. In some examples, a circuit-switching scheme or network tunneling scheme, such as Asynchronous Transfer Mode (ATM) over router networks, link emulation using the Internet Protocol (IP) or the Multiprotocol Label Switching (MPLS) protocol, and High-Level Data Link Control (HDLC) over IP or MPLS is more appropriate. In some cases, a client MPLS network utilizes MPLS internally, and also uses a service provider MPLS core to transport MPLS traffic between remote client sites.